Fuel Filling Issues

[Grant Gourley]

New to me '03 996 C4 Cab 28k miles, just back from a post purchase inspection at the indy. CEL P0455 popped on the way home and today I'm unable to fill the gas at all. It just immediately burbles out like the tank it already full or the line to the tank ia blocked. Mind you this also my first attempt ever filling the vehicle but I've pretty conclusively ruled out operator error. Going to be getting at the evap canister tomorrow to see if maybe the line was kinked putting the wheel well cover back on or if it's something more serious. New fuel cap also on the way but don't think that is probably the culprit given the filling issues. Will update as requested.

[Loren]

 

You should ask your dealer for these TSBs. I can not give you copies for copyright reasons.

 

 

 

 

 

 

 

[judgejon]

This happened to me with my 2003 996 C4$.  There is a sensor on top of the fuel tank that I believe relates to fuel pressure in the tank.  If the sensor goes bad the tank filler valve in the fuel line won’t open and you can’t fill using a gas pump.  You can still pour gas in slowly by using a funnel.  The sensor is a bear to get to.  The battery tray has to come out.  My issue was that a mouse had nested and chewed the sensor wire apart. Really.  Check the search engine on the forum.  Others have had the same issue.  It takes some time to get to the sensor wire and put everything back together.  Fixing the wire itself takes about 2 minutes. Good luck.  

[Grant Gourley]

Thank you both for the prompt replies! Loren, I did download the "Fuel Tank Hose Modification" TSB seems promising. Judgejon, I think pulling the battery tray and getting at that sensor will be my first attempt at remedying the issue. I know it's a pain to get to but I'd imagine probably still easier than pulling the tire and wheel well... Indy also reported some signs of rodent nesting in the vehicle so perhaps they've gotten up into the wires on mine too... Rats! 🐀

Edited September 18, 2023 by Grant Gourley

[Grant Gourley]

Well I didn't get very far and already found a disconnected line... any ideas as to what this one is for/where it plugs back in?

[judgejon]

No clue. keep striving. Good luck

[Silver_TT]

battery vent tube....? I can see the little hole there it looks like it should be plugged into

[Grant Gourley]

Definitely battery vent tube, wasn't hooked up as this is a sealed batt.

 

Looks like the tire and wheel well comes off tomorrow to get at the fuel vent valve.

[judgejon]

What you’re doing isn’t going to solve the fueling issue, imho.  Good luck

[987_RDC]

On 9/17/2023 at 9:31 PM, judgejon said:

This happened to me with my 2003 996 C4$.  There is a sensor on top of the fuel tank that I believe relates to fuel pressure in the tank.  If the sensor goes bad the tank filler valve in the fuel line won’t open and you can’t fill using a gas pump.  You can still pour gas in slowly by using a funnel.  The sensor is a bear to get to.  The battery tray has to come out.  My issue was that a mouse had nested and chewed the sensor wire apart. Really.  Check the search engine on the forum.  Others have had the same issue.  It takes some time to get to the sensor wire and put everything back together.  Fixing the wire itself takes about 2 minutes. Good luck.  

 

To add some info: The sensor under the battery on the Turbo and C4 is Porsche Fuel Pressure Sensor 99660620500 – Bosch 0261230015

 

I recently painted my battery tray and was wondering what that is since it looks like missing a tube attachment but I believe just to sense the pressure in one of the tank lines.

Edited October 11 by 987_RDC